Hope it's not too late to respond to this... lapushka you said it might be your ad-blocker but you mentioned reloading the website a few times while it was slow,

depending on how quickly you were reloading it, it might just be the website working as intended, giving you the Captcha test to see if you're human. If someone were to try to do something like scrape data or find vulnerabilities then it would also result in too many site requests in a short amount of time... and their methods would then fail such checks. but once you finish your humanity check everything should be ok on your side